1. Field
The present disclosure relates generally to electronic circuits, and more particularly, to suppressing overshoot voltage glitches in a class D amplifier.
2. Background
Portable electronic devices are widely deployed to provide various capabilities such as viewing and hearing of video, music, voice, and other multimedia. In order to hear the audio portion of these capabilities, an audio amplifier is used to drive a speaker to produce sounds. Additionally, the audio source signal types can be of varying quality and bandwidth. Accommodating the myriad of source signal types can increase the complexity of an audio amplifier design.
There is a continual growth of users of portable devices which have the ability to play audio in its various forms while keeping a device size to a minimum. To minimize the size of a device, manufacturers typically incorporate increasing functionality into an application specific integrated circuit (ASIC) instead of discrete components. In order to amplify an audio signal so that it can drive an external speaker, the power amplifier must be able to increase the power of the source signal.
Output amplifiers are commonly used in various applications such as audio power amplifiers, telephone line drivers, etc. Output amplifiers may be categorized into different classes such as class A, class B, class AB, and class D. Class A, B, and AB amplifiers are linear amplifiers that operate in a linear region. Class D amplifiers are switch mode amplifiers that operate in triode and cut-off regions. Consequently, class D amplifiers can typically achieve much higher power efficiency than linear amplifiers.